The present invention relates to a coupling and, particularly, one for coupling a water supply line to a water meter.
In recent years, in order to reduce exposure of individuals to lead in their water supply systems, federal and state government agencies have issued regulations that provide standards for acceptable levels of lead in drinking water and the amount of lead that can leech from plumbing fittings. In order to meet these specifications, several low lead alloys are being employed in plumbing fittings. Fittings made of low lead alloys, however, are somewhat expensive and costly to manufacture. Plastic fittings have become popular as an alternative to the higher priced copper and bronze plumbing fittings and tubing but, for some applications, they may not provide the desired strength and durability.
As a result, and particularly where fastening fittings, such as union joints and the like are involved, plastic fittings, such as coupling nuts have been reinforced either internally or externally with metal. U.S. Pat. No. 4,682,797 shows one approach to composite polymeric and metal pipe fittings. It would be desirable to provide a universal polymeric fitting which is sufficiently strong, such that it can be employed in plumbing systems which are substantially lead-free.